Fix the port for Panko API

Fix the port for Panko API

The port used for Panko is conflicts with Trove[1]. According to the
official documentation[2] this should be 8777. The 8777 port has been
occupied by ceilometer. So set the panko api port to 8977.

[1]https://github.com/openstack/trove/blob/master/etc/apache2/trove#L20
[2]https://docs.openstack.org/developer/panko/install/manual.html#installing-the-api-server

Change-Id: I5ccfc97765fc8b8bf9686b2451eda9c44c77dffc
Closes-Bug: #1691283
Depends-On: I53b286d1d6466b574fdb286cc45f3138f96dff59